Simplify the following expression: $\sqrt{90}+\sqrt{40}-\sqrt{160}$
Answer: First, try to factor any perfect squares out of the radicals. $= \sqrt{90}+\sqrt{40}-\sqrt{160}$ $= \sqrt{9 \cdot 10}+\sqrt{4 \cdot 10}-\sqrt{16 \cdot 10}$ Separate the radicals and simplify. $= \sqrt{9} \cdot \sqrt{10}+\sqrt{4} \cdot \sqrt{10}-\sqrt{16} \cdot \sqrt{10}$ $= 3\sqrt{10}+2\sqrt{10}-4\sqrt{10}$ Finally, simplify by combining the terms. $= ( 3 + 2 - 4 )\sqrt{10} = \sqrt{10}$